Question

table: user

| user_Id  | my_threads          |               
| 100      | 200:1, 201:2, 217:4 |
| 101      | 200:1, 215:3, 217:4 |

Table: thread

| thread_id | author_id | title                     |
| 217       | 100       | This is title thread      |
| 200       | 101       | this is only test         |

When the user login successfully $userId=user_Id, show title of that user threads?

select title 
from thread
where FIND_IN_SET(thread.thread_id,(select my_threads from user where user_id=100));

this sql above works when my_threads no colon like this 200, 217

Answer 1

try this:

replace your colon to commas

select title 
from thread
where FIND_IN_SET(thread.thread_id,
        (select replace(replace(my_threads,':',','),' ','') from user where user_id=100))

SQL fiddle demo